You can try this 30 MB ISO download in
http://www.slackware.com/~alien/slackboot/mini/12.1/ - it is the "mini" installer for Slackware 12.1. It should boot on your Epia just fine by default.
If yes, you should let it boot all the way to the command prompt and then run "fdisk -l". If you see disks and disk partitions, then Slackware is spot-on for your box.
I sure hope so, because I was planning on replacing Slackware 11.0 on my Epia media centre box with 12.1.
BTW: this mini installer does not have any installable packages on board - instead it is intended for network installs, or installs from a local disk partition. But if you decide you want Slackware you may just as well download the complete DVD ISO.
Good luck, Eric